Willis Lamm's
Traffic Signal Collection

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  Marbelite "Dog House" Signal

"Dog house" is a name applied to signals that had two columns of yellow and green signals below a single red head. Dog houses are most commonly used to indicate protected left turns.

Originally, most protected left turns either involved a separate signal (drivers could only turn left on a green arrow) or a fourth signal section would display a green arrow to indicate when a left turn was protected. In the four section display, the green arrow might overlap a green ball or be a separate display. (See Old Timey Protected Left Turns.)

Over time, traffic engineers decided that a yellow display should be added to warn drivers that the protected left turn movement was ending. The addition of a yellow arrow meant that a 5-section signal was required.

Five sections produced a pretty long signal that was problematic in some span wire and mast arm configurations, so the idea came about to place the through and left turn sections side-by-side under the red section.

This particular dog house signal is interesting since the red section is actually older than the lower sections and illustrates the distingushing characterists of Marbelite's T-19408 style signals.

Please note: To see some of the features described you may have to click on an image to bring up a larger copy in a new window. This signal is still obviously awaiting restoration. The photos on this page will be updated once the signal has been restored.

The logo parallelogram on the older head slants up
from left to right while the parallelograms on the
newer heads slant down from left to right.
TL-4777 "short lightning bolt" lenses.
The mounting pads for the visor screws are larger
on the newer heads to accomodate the thinner doors.
Note the different door thicknesses.
The gasket on the older head is in the housing.
The gasket on the newer head is on the door.
The older reflector has a pigtail spring hinge
while the newer reflector uses a coil spring (lower left.)


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